Railway cab signaling and train-control system



April 23, 1929- P. R. DESCHERE 0,

RAILWAY CAB SIGNALING AND TRAIN CONTROL SYSTEM Filed June 25, 1 2 Sheets-Sheet 2 O 105 101 i" O(2. 5 4

PatentedApr. 23, 192.9.

* un rso STATES PATENT OFFICE.

PAUL R. DESC'EERE, 01

new 203K, 1v, Y.,.AssI'Gnon T0 .rnn UNION SWITCH & SIGNAL cenirnnv, or swIssvALn, )EENNSYLVANIA, A. CORPORATION orrnNnsYLvAnIA. V

RAILWAY CAB SIGNALING AND TRAIN-CONTROL SYSTEM.

Application filed June 23,

This invention relates to railway jbloek signal systems andniore particularly to a system of the above type in which the move ment of a railway train is automatically controlled in accordance with the condition of the track in advancevof said train. lVith regard to its more specific features, this inve tion relates to a cab-signaling and train-control system of the type employing alt rnating currents.

fine of the ob ects of this invention is to pro-videa practical and, effective railway signal system that-will combine a high degree of simplicity of construction with maximum reliability of operation.

Another object-lies in the provision of a signal system for automatically indicating in a moving railway train the condition of the track in :ulvance'thereof, and for automatically co ring the movement of the train accord. g tosuch conditions Another object of this invention is to provide a cab-signaling i ni; ""lllfillI-CODl'lOl system of the above nature, in which effective cooperation between the trackysignal circuits and the train circuits is accomplished without the use of contact rails or wires, or sliding current collectors on the running rails or rotat qequipment. g

This inv i has for another of its objects the ovision' of a cab-s naling and train con.,.ol s steur of'high eiiicicncy of ion and of low energy consumption, iout imp inset of the reliability of ..on of said syste 1. Another object or this invention to provide means for using effectively apparatus -will be er'aemolified in the construction herel. I

inafter described, and the scope of the application of which will be indicated-in the following claims. I r j I In the accompanying drawings in which is shown one of "severalpossible embodiments of this invention,

Fig-33.. 1 is dia "aromaticrepresentation of a portion of il way track showing the electric signal circuit-s associated therewith, a d V Irelay 41,1 ai l 1917. "serial No. 176,457.

Fig. 2 is a diagrammatic representation of thesignal and controlcircuits mounted in a convenient part of the train. I 7

Similar reference characters refer to similar parts throughout. v l

Referring now to Fig-1 of the drawings, there is shown diagrammatically a portion of a railway track comprising the rails 3-l, divided into signal sections or blocks 20 41-O608O of convenient lengths by suitable insulating joints, as at 5-6, for example. Extending parallel to the track 34t is a tra'nsn lssion line 7-8 connected to a source of aternating current,preferably of a suitable low frequency convenient for operating track relays of theusual type, one of which as l-1, is associated with each signal section 40. Connected to the transmission line 78 and individualto each signal section, 2e40, is a,tracktransformer, 4-2 comprising a primary winding and two secondary windings id-45, for transforming the current of the signal circuits from the transmission voltage to aconvcni ent track voltage. The one secondary winding as i l of the track transformer as 42,is connected: to one winding 46 of the relay 41, and serves to energize permanently that winding of the relay. The othersecondary winding d5 of the track transformer is connected through a suitable inductance 47 directly across the rails of the preceding signal section {50, and serves to energize the winding 68 of track relay 61 associated with section 50. Likewise the Wllltllfi'" {l8 of relay tr associated, 'withthe signal section ll) d its energizing current from the secs winding of the transformer 22' asaoeiaw. with the section 20, to which secondary it is connected through a suitable inductance 27 and the rails of. section 40.

Thus, the energization of winding 48 of the hence the operation of the latter, dependent upon the condition of the track section with which that relay is associated.

"l lxtending likewise parallel to the track 3+4 are the cii'cuits ,9-1O and 10-11, which-may have-one conductor 10 in common,1connected respectively to, sources of alternating current of differing frequency, which will. he .designated as caution fre: quency and clear frequency respectively.

These two frequencies are so selected that, I

with the frequency of the transmission line 78, they do not constitute rational multiples of one another, thereby avoiding harmonic interferences therebetween, Fur thermore, frequencies of such values are selected that they may be readily separated one from. another by suitable resonant circuits to he hereinafter described.

To the circuit 9-40 of caution frequency there. is connected primary of a transformer 51, individual to the signal section 5.0, for transforming from transmission voltage to suitable track voltage. Secondary winding 52 of the transformer 51 is connected through relay 41 to the rails 3- 1 of the preceding sigi'ial section 00, over the follo\\iin, ,g; circuit: from secondary 52, conductor 53, contacts of relay ll, and conductor 5-1 to rail 3 of section rail 42 of the section 10 with which relay ll is associated. v

Likewise the transformer 56 is provided to transform the voltage of the clear fre quency circuit 10-11 from line voltage to track voltage. The secondary 5'? thereof is connected across the rails 34l of the second preceding gnal section 80 through contacts of relays 11 and (51, over the following circuitzfrom secondary 57, conductor 58, contacts of relay 11, conductor 59, contacts of relay 6.1, conductor 74 to rail3 of section and from rail l over conductor 7 5 back to secondary 57. In this manner a voltage of clear frequency is impressed across the rails of signal section 80. v

' in like manner through the entire railway track, all the caution frequency transiloriner secojiularies are. connected through the contacts of one track relay to the rails of the preceding signal section, and the secondaries of all clear frequency h'iaDS'fOllXl617E; d through the contacts of two to the rails of the second preeach section having impressed across its rails voltages of both cantion and clear frequencies. v

vSuitable condensers and inductances or choke coils are placed in-the several circuits to prevent interference between the circuits of different frequency and to prevent reactions of one circuit upon the other.

Turning now to Fig. 2, thereare shown the signal and control circuits as mounted in a cab of a railway train, it being undcn.

stood that by cab is meantany suitable 'inountcd on the axle 102 and forming a )art of the runnine' 'earof the train or loco- I D L l t: v 1 mon re and irefcrabl constitutin the lead 102 constitutes the primary.

Connected to the secondary winding 103 of the axle transformer and in multiple with one another, are the primary windings 10511118; 106 of the tra sformers 'l and T. In the circuits of the primary windings 105 and 106 are espectively condensers C and U and inductances L and L in series therewith. The capacity of the condenser C and the value of the inductance Lin the circuit of the primary105 of transformer T are so adjusted that their associated circuit is vin resonance with respect to vthe caution frequency, and hencethe transformer primary 103 will carry a current only of caution frequency, the currents; of thereinaining frequencies being prevented from passing through the tuned circuit by reason of the values of the capacity and inductance in that circuit. Similarly the circuit of the primary 106 of the transformer '1" is resonantly tuned with respect to thecurrent of clear frequency and hence allows transformer primary to respond only to the clear frequency current. 1

To the secondary windings and 106 of the transformers T and T, respectively,

are connected the amplifiers 10'? and 108,

which may be of the audion type, used. in wireless telegraph worli and whicii coiuprise accordingly the batteries li- "(and ll ;l.,,. respectively, for intensify or thereby. A second amplifier 1101:0ay be connected with the first amplifier 108 by amilif in the current vibrations received means of transformer T for producing a further amplification of the current variations. V Y

Connected to the amplifiers lO'Yand 110 respectively are the frequency in 109 and 11 2, which are preferably of the TQSISiT- ance-reactance or split-phase type and. which are of convenient range of operation to re-- spend r spectively to the currents of caution frequency and clear frequcncy. The fire quency meter 112 controls, contacts controlled bythe moving elem-eihereof, an auxiliary op" ting circuit 111 including a battery 1. and an electric-bell 113, or some; other suitable device for visibly or audibly giving an indication. Free manner coutrols au aiiiz-dliary circuit 110' con'n iency met-er 109 in like ment of the frequency meter.

' 1,71o,5oo

. may constitute the throttle valve in the 7 direction indicated by the arrow 115 will steam circuit of a steam locomotive or suit-' able switches in the electric circuit 'COIIT trolling the current to the propulsionmotors in the case'of an electric train.

Preferably the device controlled by the solenoid 11 i is the air valve controlling the air brakes throughout the entire train.

The operation of this system is substantially as follows: Normally each signal section as 80 has impressedupon it the voltages of caution frequency and clear frequency over circuits similar to those previously described and controlled by the several. track relays. A train approaching in section 80 in the close the circuits of caution. frequency and clear frequency, of which circuits the rails 3- 1 of section 80 form apart, through an axle 1052 of the train. The alternating currents of both caution and clear frequencies pass through the axle 102, which fern'isthe primary winding of the car axle transformer.

Eng 1023 and are conduct-ed to the cab signal circuits. The current of cautionfrequency will pass through the primary 1050f the transformer T through the circuit comprising the condenser Cand the inductance L, the magnitudes of which, as" heretofore described, are adjusted to give a resonant condition with a current of caution fre, quency. Currents of clear frequency,'as well as of the frequency of the transmission line which may be induced in the secondary 103 of the car axle transformer, are prevented from passing-througlrthe primary 105 by reason of the circuit in series therewith.

frequency will be induced in the secondary 117 of hetransformer T, to which the isconnected. 107 will intensify or amplify the variations or oscillations of current of caution-frequency and will transmit such amplified current to the frequency meter 109, thus causing the 'meter to indicate constantly the caution frequency and to hold closed the circuit 116. Similarly, by reason of the characteristics of the circuit ofthe p imary106 of'the transformer T, the primary 106 will receive only current of clear frequency, the currents of other frequencies being substantially tuned out. Currents of clear frequency will be induced in the secondary 11,9 of transformer T, the variations thereof'being amplified successively by the Currents of the same frequcncies are induced inthe secondary WlIlCl-L Hence, a current of, caution" The amplifier amplifiers 108 and 110, and then transmitted to the frequency meter 112. Meter 112 will accordingly give a constant indication of the clear frequency and will held open at its associated contacts the auxiliary operating circuit 111., Hence with both caution and clear frequencies affecting the, frequencymeters 109 and 112, the auxiliary operating circuits are held closed and open respectively,and the circuits coi'itrolling the train control apparatus held inoperative, allowing free advance movement of the train.

If, however, a train be present in the section 10, the oil-coming train in section will'receive an immediate indication of the presence of a train in the second section in advance thereof, A train in; section shortcircuits the" winding 18 off relay associated with the section 10. "Relay being then under the influence of .coil 46 only,'thereupon operates "to open its associated contacts, thereby opening thecircuit of the clear frequency current, previously traced, impressed upon/the rails of section 809 Theclear frequency current thereby cut 0E from the signal circuitin the train cab, leaving only the currentof caution freque cy in its respective clrcuit. element of frequency meter 112, responsive to clear freqiiiency' flimmediately moves to 'Zero indication upon the cessat on of the cur-' rent :of clear frequency and closesithe auxili The moving ary v-operating'circuit 111 at its associated contacts to operate an electric bell 118 indicate audibly the presence of a train in the second section ahead, thus indicating tothe operator the necessity 'forprcceeding with caution.

If, on the other hand, there is atrain' in the section 60 immediately ahead of the section 80 of the approaching train, rack relay 61 operated byreason of the shortcircultmg by thetram in sectiouGOof the Winding 68, thereby opening of danger and frequency meter 109 opens at its associated contactsthecircuit' 116, to the solenoid 114 t0 eperatepreferably the air valve 118 in'the air brake circuit of the train,"thereby bringingthe'train to a stop. The solenoid 114: is so connected with the air valve 118 that a de-energization thereof, eitherby the openingof its circuit by the meter 109or by an accidental rupture of itscircuit, will actuate the valve 118to cause the operation' of the b'rakescf the train.

at its assoelated contact-s thecircuits of both caution and clear frequency impressed upon section I to such track conditions.

the train to a stop.

secondary'lli' or 119. It in such case the ordinary electromagnetic relay were -employcd, in secondary circuits 117 and 119,

one of these relays might operate to indicate a danger or to throttle the engine also, while the road ahead is unobstructed.

In the embodiment of this invention herein set torth, only one track of a multiple track system is shown with its associated signal circuits, but it is to be understood that similar signal circuits maybe readily applied to the other tracks of such a multiple track railway. It is to be noted that a single signal circuit may be employed instead of the two circuits herein shown without departing from the spirit of this invention.

it will be seen that there is provided' herein a train signaling and control system in which the condition ot the track in advance of an approaching train s positively indicated at all times inthe train itself and in which the further movement 01 the train is controlled automatically according Furthermore, it will be noted that the control circuits and signal circuits associated therewith, are preterably of the closed circuit type, whereby a maximum reliability of operation and safety is-attained, since either an intentional or accidental breakage of a circuit will immediately give a danger signal and bring It is also to be noted that a signal and control system has been provided, whiclrniay be used with direct current as well as with alternating current imtallatiiiins, and that this system is easily adapted to employ the many forms ot sig naling apparatus and devices used in railway signal work. it will further be seen that there is provided a system in which the several and other advantageous objects of this invention are effectively achieved.

as various possible embodiments might be made of the above invention and as various changes might be made in the embodiment above set forth, it is to be I'HIdGiSiTOOd. that all matter herein set forth or shown in the CCOii11)ll'il' l11g drawings is to be interpreted illustrative and not in a limiting sense.

I claim as my invention:

1. In a railway locomotive, a signal circuit, means for coii'ununicating currents of different frequencies, troma main track circuit to said signal circuit, means in said signal circuit responsive to onertrcquency for indicating a track condition, and means in said circuit responsive to another frequency n i v.5.

for connecting one of said sources to a preceding section and another of said sources to a section preceding aid last section.

3. In a railway block signal system, a

track divided electrically into sigi'ial sections, a track circuit associated with said I signal sections, a relay operatively relat d with said track circuit and with each of said signal sections and. adapted to be con-.

trolled by its associated si nal section, a

plurality 01? current sources oi" varied quencies, one of said. sources being connected I through said relay to the'preceding signal section, and another said sources being connected through 7 section preceding said last section.

(i. In a railway signal system, a track divided electrically into signal sections, 'a traclr circuit associatedwith said signal sections a relay operatively related, with said track circuit, with each of said signal sections and adapted to be controlled thereby,a plurality of current sourc of varied frequencies, said relays controlling theconnection'ot said sources to said signal sections; signal circuits in a'railway ear cacli' of WlllCli iS adapted to respond to one of said trequencies,-means for communicating currents from said signal sections to said signal circuits, a device for indicating the frequency of said currents in each of said signal circuits, and auxiliary operating circuits controlled by said devices. V

, 5. In a railway signal system, a tract: divided electrically into signal sections, a track circuit associated with said signal sections a relay opcratively related with said track circuit, with each of said signal sections and. adapted to be controlled thereby, a plurality of current sources of varied frequencies, said relays controlling the con nection of said sources to said signal sections; signal circuits in a railwaycar o of which is adapted to respond to one of frequencies, means for communicating currents from said signal sectf ns, to signal circuits a device tor indicatin frequency ot'said currents in each oii said relay to the signal said lilO' signal circuits, and an auxiliary operating carrying currents of di'llerent trequencii-s,"

indicating devicesin a railway car, one rosponsive to each of said. currents, 11182111SL0- tuated by the presence of a train preceding said car for breaking one of said circuits, and other means similarly actuated for breaking other said circuits.

7. In a railway signal system, incombination, a pair of circuits for carrying alternating currents of different frequencies, electromagnetic switches in said circuits for normally maintaining them closed and an other clrcuit under the influence or a train,

and means for permitting the axle ofa prcswitch to affect said circuits.

cedin train to short-circuit a coil of circuit of a definite frequency passing through one pair of contacts to the prc ceding block, and a second alternating current passing through said other pair of contacts to the block preceding said latter block. V In testimony whereof, I have signed my name to this specification this 20th day of June, 1917.

PAUL R. nnscnnnn. 

